There was a time when if you wanted colorful leaves in partial sun to somewhat shady exposures, coleus was your only option. That was then, but Alternanthera is now.

Alternanthera (al-ter-NAN-the-ra) is a genus of perennial ground covers and sub-shrubs that bring vivid foliar color — enough to earn them the generic moniker of Joseph’s coats — to summer gardens.

I first saw Alternanthera ‘Jewel,’ a cultivar with pink, copper, gold and green foliage at the Getty Center garden in Brentwood a decade ago. Yet you still have to search high and low to find Alternantheras.

Alternanthera ‘Raspberry Rum’ (Photo courtesy Ymker Greenhouse)

Alternanthera reinickii, with scarlet foliage, is the most easily located species since it grows underwater and is meant for aquarium use. Other Alternantheras, it seems, can be grown as either dirt garden or water garden/pond plants. This is also true of closely related Iresine herbstii, the bloodleaf plant, whose luminous foliage is the reddest in the botanical kingdom.

So far, I have not located a nursery in California that grows Alternantheras. I did, however, find them on eBay, Amazon and provenwinners.com. They also are available through a number of mail order nurseries throughout the U.S.

Vintage Green Farms (tom-piergrossi.squarespace.com), a Hawaiian nursery, has an impressive collection of Alternantheras and many other jaw-dropping plants available for shipping.

Do not be concerned about shipping costs. I learned that since FedEx sends far more packages to Hawaii than it brings back, and since it does not want to return with half empty planes, it drastically reduces shipping rates to the mainland so that, in Los Angeles, you pay about the same to ship from Hawaii as you do from Northern California.

This is great news since the selection of exotic plants in Hawaiian nurseries is much more extensive than in California and many of them will grow here — if not outdoors, then indoors.

Here’s the rub with Alternantheras: they are extremely cold sensitive. Although perennials, Hawaii and coastal Southern California are the only places where they have a chance to consistently make it through the winter. Then again, the same is true of coleus and impatiens, yet everybody plants them.

I should mention that I have succeeded in shepherding Alternantheras through the winter by planting them under a tree near a tall hedge so that they were snugly protected from the cold.

And there is no reason why you cannot dig up and pot your Alternantheras — before cold nights come — and transfer them to a sunny exposure indoors for the winter season.

Another option is to take cuttings — which root as reliably as coleus cuttings — before winter arrives, nurture them indoors in pots in a fast draining soil mix, and then plant them back out in the garden in spring.

And here I am compelled to sneak in Plectranthus ‘Mona Lavender,’ one of my favorite plants, although its foliage is not spectacularly colorful. Yet ‘Mona Lavender’ leaves are unique in being the darkest of dark green on top and splendidly violet-purple underneath.

The flowers, which begin blooming now and will continue to do so through the fall, are either pink or lavender-violet, depending on the variety.

‘Mona Lavender’ can take as much shade as any perennial, including Clivia, that silky orange flowered beauty with strap-like leaves that blooms in the winter.

For more information about area plants and gardens, go to Joshua Siskin’s website, thesmartergardener.com. Send questions and photos to Joshua@perfectplants.com.

Tip of the week

‘Mona Lavender’ has a quality, astonishing to say the least, that I have not seen in any other flowering perennial. You can take semi-woody stem cuttings as long as 12 inches in length and root them in water.

Strip the leaves off the bottom third of any ‘Mona Lavender’ cutting and roots will form all along the portion of the stem that is submerged.

Once you have a thick crop of roots, within 6-8 weeks of the stem being plunged into water, you can plant the cutting directly in your garden, as long as the soil is soft and drains well.